Watch: Workers Risk Their Lives to Fix the Great Wall of China

Tethered by a simple rope held by a partner, workers balance from precipitous heights to repair one of the world's most famous structures.

One of the most rugged stretches of the Great Wall of China is undergoing repairs to its centuries-old structure—and workers are risking their lives to do it.

Efforts to repair the iconic wonder of the world have been ongoing since 2005, and the recent restorations in the Jiankou section of the wall demand intense physical labor.

Video filmed on June 12 shows some of the most perilous work, including laborers hanging from soaring heights. With ropes tied around their waists, repair workers spread cement on the wall's steep sides, while others hold the ropes for support, the fate of their teammates dangling perilously in their hands. Surviving a fall down the steep sides would be unlikely.

In the video, filmed by Live China, a laborer explains why he risks his life to make repairs to the ancient structure, saying the job is an honor.

"The work is mainly bricking. If you’re timid then you can’t do it, but I’m brave…it’s very dangerous," a man says in the video. (Quotes have been translated from Mandarin.)

"It’s very dangerous. It’s windy underneath."

Getting supplies to this unforgiving portion of the wall is also a taxing endeavor. Because the path is so steep, donkeys and mules must be used to transport bricks, which can weigh as much as 300 pounds each.

According to the local paper, Shanghai Daily, restoration is done with bricks that have fallen from the wall over the past centuries, when they're available. Bricks that must be manufactured for the Great Wall are done with historical accuracy to preserve the structure's original makeup as much as possible.

“We have to stick to the original format, the original material and the original craftsmanship, so that we can better preserve the historical and cultural values,” Cheng Yongmao, the engineer leading Jiankou’s restoration, told Shanghai Daily.

The work is often grueling, requiring a 40-minute trek with donkeys and supplies to the repair site. The crews descend the mountain as the sun sets, saying they leave exhausted.

Repairing the Great Wall is a source of so much national pride that any lapse in attention to historical accuracy can draw outrage. Repairs to a portion of the wall in September of last year drew ire after cement was paved over a path. At the time, the New York Times likened the repairs to "a cement skateboarding lane dumped in the wilderness."

The portion of the wall currently being repaired is famous for its rugged beauty. It was built in the 17th century during China's Ming Dynasty. Some portions of the wall, however, date as far back as 2,000 years.

While it's a popular misconception that the wall can be seen from space, the Great Wall is considered one of the seven wonders of the world and one of the greatest feats of architecture. The most recent archaeological surveys, conducted in 2012, estimate the wall to be over 13,000 miles long. (Also see "'Lost' Great Wall of China Segment Found")

Hundreds of years ago this barrier was used as a source of defense and a method of imposing duties on imports.

Today the wall is a popular tourist destination that sees over 10 million visitors annually.

Repairs have been overseen by district governments, which plan to continue the work. Talking with the South China Morning Post, Dong Yaohui from the China Great Wall Association noted that repairs previously done for the sake of attracting tourists were now being done to preserve the historic site for future generations.